I have an old STD PROD imported by Navy Arms that I thinking of upgrading by adding an Ultimak rail and Choate stock. Will eventually get an economical Aimpoint/clone for it. It looks like Choate makes 3 different stocks: standard pistol grip, folding pistol grip, and a M4 collapsible clone. I'm leaning more for the standard as it's 1/2 the price of the collapsible (which are hard to find) and 2/3 the price of the folding, besides it looks like it will work better with a 3-point sling. Any and all comments/feedback is greatly appreciated.